Method and Apparatus for Processing Metalline Sludge

Abstract

The invention relates to a method for processing a metal-bearing sludge in conjunction with a metal separation process. According to the invention, the sludge ( 13 ) produced in the metal separation is classified based on a predetermined property of the sludge into a better ( 15 ) and a worse ( 17 ) substance fraction, as the process is concerned, and the worse substance fraction ( 17 ) is removed from the process and the better substance fraction ( 15 ) is returned to the process.

1 . A method for processing a metal-bearing sludge in cobalt removal that is performed in conjunction with zinc preparation process, wherein the sludge produced in the metal separation process is classified based on the surface activity of sludge particles into a better and worse substance fraction, as the process is concerned, and the worse fraction is removed from the process, and the better fraction is returned to the process. 
     
     
         2 . The method as defined in  claim 1 , wherein the metal-bearing sludge is a product of a precipitation process. 
     
     
         3 . The method as defined in  claim 1  wherein the metal-bearing sludge is settled in a metal separation reactor prior to the classification. 
     
     
         4 . The method as defined in  claim 1 , wherein the solid matter content in the reactor is adjusted to be in the range 10-200 g/l. 
     
     
         5 . The method as defined in  claim 1 , wherein the classification is performed based on the granular size of the sludge particles by dividing the sludge into a coarser and finer fraction. 
     
     
         6 . The method as defined in  claim 1 , wherein the classification is performed using a device based on the centrifugal force. 
     
     
         7 . The method as defined in  claim 6 , wherein the classification is performed using a hydrocyclone or a similar device. 
     
     
         8 . The method as defined in  claim 1 , wherein the underflow of the classification device is a worse fraction from the standpoint of the process. 
     
     
         9 . The method as defined in  claim 1 , wherein the overflow of the classification device is a better fraction from the standpoint of the process. 
     
     
         10 . The method as defined in  claim 1 , wherein the fraction that is worse from the standpoint of the process contains mainly coarse fraction. 
     
     
         11 . The method as defined in  claim 1 , wherein the fraction that is better from the standpoint of the process contains mainly fine fraction. 
     
     
         12 . The method as defined in  claim 1 , wherein the classification is performed in batches or continuously. 
     
     
         13 . An apparatus for processing a metal-bearing sludge in cobalt removal that is performed in conjunction with zinc preparation process including one or more metal separation reactors, a feeding device for introducing raw material into the metal separation reactor and a junction line for removing the sludge produced in the metal separation from the reactor, wherein the apparatus includes a classification device which is arranged in conjunction with the pipe extending from the metal separation reactor and which is arranged for classifying the sludge based on the surface activity of sludge particles into a better and a worse substance fraction, as the process is concerned, and recycling means for returning the better substance fraction to the metal separation reactor, and means for removing the worse substance fraction from the reactor. 
     
     
         14 . The apparatus as defined in  claim 13 , wherein the classification device is placed substantially in conjunction with the metal separation reactor for removing the sludge settled on the bottom from the bottom of the reactor. 
     
     
         15 . The apparatus as defined in  claim 13  wherein the classification device is based on the centrifugal force. 
     
     
         16 . The apparatus as defined in  claim 15 , the classification device is a hydrocyclone or a similar device. 
     
     
         17 . The apparatus as defined in  claim 13 , wherein the classification device is arranged to function in such a manner that the underflow of the device is the worse fraction from the standpoint of the process. 
     
     
         18 . The apparatus as defined in  claim 13 , wherein the classification device is arranged to function in such a manner that the overflow of the device is the better fraction from the standpoint of the process. 
     
     
         19 . The apparatus as defined in  claim 13 , wherein the classification device is arranged to function in batches continuously. 
     
     
         20 - 21 . (canceled)